Class: DS::Stack

Inherits:
Object
  • Object
show all
Defined in:
lib/ds/stacks/stack.rb

Overview

Class implements Stack data structure. Internaly uses array or linked list to store elements.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Stack

Returns a new instance of Stack.



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# File 'lib/ds/stacks/stack.rb', line 5

def initialize(*args)
  first = args.first
  @store = if first.is_a? List
             first
           else
             args || []
           end
end

Class Method Details

.create(*args) ⇒ Object

Creates stack internally implemented as List



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# File 'lib/ds/stacks/stack.rb', line 15

def self.create(*args)
  new(List.new(*args))
end

Instance Method Details

#empty? ⇒ Boolean

If stack is empty returns true otherwise returns false.

Returns:

  • (Boolean) 


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# File 'lib/ds/stacks/stack.rb', line 40

def empty?
  store.empty?
end

#peek ⇒ Object

Returns element from the top of the stack.



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# File 'lib/ds/stacks/stack.rb', line 35

def peek
  store.last
end

#pop ⇒ Object

Removes element from stack and returns it.



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# File 'lib/ds/stacks/stack.rb', line 25

def pop
  store.pop unless empty?
end

#push(x) ⇒ Object

Adds element on the top of the stack.



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# File 'lib/ds/stacks/stack.rb', line 30

def push(x)
  store.push x
end

#size ⇒ Object

Returns the stack size.



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# File 'lib/ds/stacks/stack.rb', line 20

def size
  store.size
end